West Nile Virus
2019 Positive West Nile Map
As of June 30, 2019
West Nile virus (WNV) is a mosquito-borne disease that was first isolated in 1937 from the blood of a woman in the West Nile district of Uganda. Since then, the WNV has been commonly found in humans and birds and other vertebrates in Africa, Eastern Europe, West Asia, and the Middle East. The WNV first appeared in the United States in 1999 in New York City and has continued to spread throughout the United States.
West Nile Virus is a reportable disease. Report any confirmed or suspected case to: MT State Veterinarian 406-444-2043 and MT USDA APHIS Veterinary Services 406-449-2220.